Wireless-telegraph system.



PATENTED JUNE 19, 1906.

L. DE FOREST.

' WIRELESS TELEGRAPH SYSTEM.

APPLIOATIQN PILED PEB. 20, 1906.

4 SHEETS-SHEET 1.

H67 EEEEE WITIJ No. 824,003. PATENTED JUNE 19, 190E.

' L. DE FOREST. v

WIRELESS TELEGRAPH SYSTEM.

APPLIOATIONIILED FEB. 20. 1906.

4 SHEET8-SHEET 2.

No. 824,003. PATENTED JUNE 19, 1906.

L. DE FOREST. WIRELESS TELEGRAPH SYSTEM.

APPLICATION FILED FEB. 20, 1906.

4 SHEETS-SHEET 3.

No. 824,003. PATIENTEDI JUNE 19,1906. 1 L, DE FOREST. I WIRELESS TELEGRAPH SYSTEM.

APPLIGATION FILED FEB. 20. 1.906.

4 sums-SHEET 4.

V V V V V z E L \X/IT E5555: I

To azz'whm concern: a

.- iIIN ITED S'IAT ES NEW YORK, N;

Be it k-nown that I,--LEE DE- Fonns'r, a citizen of the UnitedStates, and a resident of New York, in the county of New York and State of New York, have invented a new and useful Improvement inlWhelessTelegraph Systems, cation. a h r My invention relates to wireless-telegraph systems in which a'closed oscillating circuit is coupled to an open oscillatingor radiating circuit and the 'ob'ect of mymvention is to provide a couple wireless-telegraph system whose natural mode of vibration shall be monoperiodic and which "shall have a greater persistency of vibration than those now commonly emplo ed.

As is now well un erstood, the resultant vibration produced by the natural oscillatory restoration to electrical equilibrium of a:

Iriled system jconsisting 'oftwo circuits, bot

of which when, isolated, havethe same natural period, isnot, in general, monoperiodic, but is multiperiodic, consisting of at least two.frequencies,'neither one of which is equal to that natural to either of said circuits. Thus if the "waves radiated by such a system be measured b a wave-meter, at least two wave lengths will be found, so that if a curve be plotted having as its ordinates the currents or potentials developed inthe wav e meter circuit and-as its abscissae the progressively-varying values of the frequencies natural to said wave-meter circuit, at least'two maxima of current or potential will be observed, and it will be'found that the frequencies corresponding to said I naxima are not the same as those natural to either of the component circuits of the coupled system. In Wireless telegra'phy' such multiperiodic vibration renders accurate tuning Impossible, for there are at least two frequencies and therefore a receiving-circuit can be attuned to either one of them; and also it renders transmission inefficient, for the. radiated energy is distributed over, or divided between,waves of two frequencies instead of being concentrated mto waves of onefrequency. Therefore in order tofrender magnetlc wavesof afsin' le frequency, and

a receiving system whic will I respond to waves of but a single frequency-1..

Specification of Letters Patent. I Application filed Potruary 20,1906. BQl'iIlHO- 302.009.-

ofwhichhthe following is a spec1fi- 1 WIRELESS-TELEGRAPH SYSTEM.

accomplishing the fore oing results. but these, 1n general, depen upon loose ,mage netlc linkage between the antennaand its associated transmitting-or. and, therefore, are unsuited commercial long -.distance wor discovered that by -making, the two paths from the top of an ant electromagnetic waves radiated temwillbemono eriodic;

[My invent1ont eref ore consists in akin" antenna to'ear'th -eqlu'al in period, so that the radiated waves, be monoperiodic, and

spark-gap, so that said waves and theoscilsistency.

M 'y invention may best be understood'by comp any and form a and which showin iagrammatic form 597'.- eral systems of circuits embodying the principles of my invention.

15 and 16 represent wireless-telegraph transmittingsystems; Figs, 8,9, 10, 11, 12, 13, 14, 17, 18, 19' and 20 represent wireless-telegraph receiving systems; and Figs. 21 and 22 are curves rawn to rectangular coordinates, in

subject to such damping effect.

employed in the transmitting systems and tenna; C, 0,, C are condensers employed in the transmitting systems and 0, 0' 0, are the corresponding condensers employed in the receiving-systems; C is a condenser em ployed. to shunt the sparkap of the trans? employed to shuntthe responder of the re ceiving oscillating c1rcuit;-Ais a transmittin 7 antenna and-Av 1s a receiving-antenna whic as shown, is a loop-antenna; R, R are oscilla receiving circuit"v I e'nna to earth equalin period, the oscillati ons-finfacoupled system will have but a single frequency, andthe' .by e d' y i r also in eliminating the damping efiect'of the lations creating them will have a greater per- -hav1ng.reference to the drawings which a 'c art of this specification which the ordinates represent current ampli tude, and the abscissae represent tiine, and which show, respectively, the modes of vi bration of an osclllating circuit subject to the damping 'efiect of a spark-gap andone not' L, L 1 L, are thecoi'responding mductances 4 1n recelvmg. systems, L 1s an inductance connected 1n one slde of a rece1v1ngloop-an'--.

PATENT oFFIoE. LnE'D E'FoREsr, 0F- i 5 reca ur 19, 19010..

I I 1 Various systems known as looselycoupled systems havebeen devised for the aforesald two paths from the twat-thi- I In thedr'awings, Figures 1, 2, 3, 4, 5,6, I

In the figures L, L,,'L,,, are inductances 1.

, 5 mittmgosclllatlng circuit; 1s a condenser IO ca acityand'eflective inductance, in both of 'W 'ch cases the product ofthe resultant cation-responders ;'."1., .T are telephones; B, B.

are batteriesjand P, Pf are adjustable resistances.-" In each of the figures, the electromagnetic oscillating circuit are so chosen that the two paths from the top of the antenna to, earth are equalinperiod. For'this purpose said two paths mayhave equal capacity and equal inductance, or may have equlvalent effective pacity by the total inductance of one of said paths will be equal tothe product of the resultant capacit by the total V inductance of the other of sai paths. r

w In Figs. 1, 2, 3, 4, 5,6, 15 and 16 the fundamental natural eriod of the antenna system y E is ma e equal to, that of the closed oscillating circuit conductivel connected thereto at the points a: and y. or example,

in Fig. 1, the said antenna system has the "1, same periodas the circuit a: CLO y C L O, in

Fi 2 it has the same period as the circuit as C dy O C, in Fig. 3 ithas the same period as the circuit a: C L C y-OL 0,850., and in all said figures the two paths from the top of the antenna to earthwill have the same period as the conductively-connected oscillatm circuits and the two components thereo included between the points a: and 'y. In all of saidfigures, except Figs. 2 and 3 two sets of oscillations having different frequencies will be developedin the oscillating circuit so long'as s arkspass' across the gap S, for in each case it ereare tWoOsciHating'circuits of different natural eriods employin .the'samev sparkap. owever, in all sai figures, including igs. -2 and 8, the sparks-cease to. pass across the gap afterione or-two oscillations because I the auxiliary-' shunt path around the ga offers less opposition to the passage of osci I lations than said gap, and thus the oscillatin system passes almostinstantly into a'close oscillating circuit which has no spark-gap or 1 other discontinuity and which therefore has afar greater persistency than one which is 'lintalli'callydlscontinueus. In all said fig aforesaid close oscillating circuit'is different and it is to the period of vferent fromthat of the circuits 0 G 'while the circuitO L 0, 0,11 Oehaseastil l different periodan'd it isto this period that the eriod of the antenna s stem 1s made e 'ua In a 2, however, t e two circuits ,O C L, are equi 'eriodicand in Fig. 3 the two circuits SLOO are 'equiperiod-ic hence in both 4 ures there will be oscillations .ofbut a sin e frequency so long as sparks pass across 516 constants of the antenna system and closed g'ap S. In Fig. 2, as soon as sparks cease to pass across the ga S, the oscillating circuit ecomes the'close circuit C C C C which is so constructed as to have the same period as that of the antenna system. However, in Fig. 3, the closed oscillating circuit C L C C L 0, formed when spar ceases at the gap has the same natural period as either of the two circuits S L .C C L, so that oscillations of but one frequency are developed in the system from the beginning to the end of the electrical movement. I

. The s'stems shown in Fi s. 4, 5, 6, 15 and 16 are a ike in principle to t e system shown in Fig. 1 and their operation will-be understood from theioregoing description. It will be noted that in each of said figures, as well as in F' 's. 1, 2 and 3, an auxiliary shuntpath aroun the s ark-gap is provided and that in Figs. 2" an 3 said shuntath forms one ofaair of. equiperiodic osci ating circuits; T e inductance L, shown serially connected in the antenna system is'for the ur- .pose of increasing the natural period 0 the 'antennas'ystem without at the same time altering the natural eriod of the closed oscillating system for t e purpose of putting the :two s stems .into syntony.

Fig. 7', I have shown an extension of the systems above described in which the original oscillatin circuit S 0, I 0, is inductively related to t 'e closed oscillatin circuit C I, I 0 by the loose-linkage transIormer M. The condenser 0 forms an auxiliary shuntath around the ap S, and as soon as spar 'ng ceases at sai gap oscillations of a sin le freuencyare developed in the closed oscillating circuit C G I, C, and in the closed oscillating circuit C I I, 'C and hence in the antenna system. Ii said condenser 0 be omitted, os-

. cillations of a single frequency will be developed from the. time of. the initial discharge acrossxsaid ga until the system regains its electrical equi 'brium,.but a greater persistency'is gained by employinfi said condenser. Inthiscase the closed osci ating circuits C C, I C,-and-O I I, C are equal in period-and the antenna system is given the sound period as said circuits. Obviously the two paths to earth fromthe top of said antenna also will aveithe'sarne period as said closed oscillatin' circuits. I 1 ig's.8,9,10,11',"12,13,14,17,18, 19 and 20. show various 'forms of receiving-circuits corresponding to-the transmittin -circuits above described and embodying, t e principles thereot; Saidreceiving-circu'its may be connected between the points w' y of loop receiving-antenna 'as shown or they may be connected to '0 en-ended antennae. "In all cases either Wit open-ended or loop antennse, the electromagnetic constants of the system are so chosen-that the two paths to earth E from the top of the antennae 2 will be equal in period. Y

' closed oscillatin circuit Fig. 8, the responders R, are @011 fiected'inthetwo, sides, reppectivel ofthe V "'1 RR C and eachis provide withja "tele hone associated battery B B, an variable shown'in Figs. .17 aIId ZO, one tele hone, which may be a head-telephone, mayb ployed-andso connected as. to receive current from both responders. 4 .In Fig. 17-, the

telephone T and battery Bare-connected in shunt across the circuit containing the-serially-connected' responders R, R," and in Fig. 20, each responder is connectedn seneswith a primary of a different one of the two transformers "M,, M ,',"wh.ose secondaries are sponds to Fig. 1, showing an arrangementof serially connected with. the telephone T. 1 3 3' It will benoted wearer each of the trans-' mittiiig" systems, there is a correspondin I re-. ceivingsystem,thus Fl :8 correspon s to Fig. 1; 9 to Fig.2; Flg. 10-to Fig. 3".Fig-. 11 to Fig. 4; Fig.12 to Fig. 5; Fi; 13"td.Fig. 6; Fig. 18 toFig. 7;Fi ..14to ig. 15; and Fig. 17 to Fig. 16'; whi e "Fig. alsojcorre;

slgnaleindic'atin app r t difierehtgsfrbm that shown in 1g. 8, and. shows a above in "connection with the transmitting systems, the natural period of the two paths,

modification of Fig. 18.

In all the receiving s ste and 19 in which the responderR is inc uded in a secondary closed oscillating circuit inductively relatedto that which is conductively connectedto the antenna system, the natural eriod of said secondary oscillating circuit aso is madee ual to" that of. the antenna system. It fol ows that as explained in, the antenna system is equal -tolthat-ofthe conductively-connected closed oscillating circuits and to each of the com onents thereof which are included between t epoints w and coupledreceiving systems will be mono eri- Under such circumstances, each of; the

odic in its naturalmode. of vibration an will respond to electromagnetic waves of but; a

i sin le definitefreguency.

'has a far dampened by the responder resistance and in T T andresist-. y ance P, P. a One te ephone maybe held to." each ear of the recelving operator, orv as e emflow of current, said responders are a he natural period of the closed osci lating circuit which is conductively connectedlbetween the points J 1w 'yzto' the antenna system isinade e ual-to .t'h'atof said antenna -system',andinF1' s. 18

of'electrical resonance due to the increased I pe'rsisten'cy of said circuit, arejtranslated to the; loosely-coupled, and therefore. resonant transformers. M ma e step-up or step-down res onder R.

Figss, 10, 11,12, 13 and 14, large.dif-d ferences of potential are developed by oscilla transformers accor ing to the natureof the tions of the proper frequency between thepoints of connection of thetbranch circuits connected acrossthe terminals ofthe-closed oscillatin circuits which include the responders, and y' such potentials or the resultin o eratecE In Figs. 18.-and 19, the primaries of the ondary I,. I

have found that the capacity of the con denser C, in Figs.- 8, 17, 19 and 20 should be additively or cumulatively upon v the" sec very large .compared to that of condensers Gand-Ol 1 I 'InFig. 21-, the curve represents'the-vari transformers Mshould referablybewound.

oppositely so th t Sai .primanes. ,wfllact 5 I ation with time of the current amplitudein-a closed oscillatingcircuit containingba sparkap' or anoscillation responder. he os'cil-. ations are relatively non-perslstent and are isochronous throughout their duration from i t to t, Circuits of whose mode ofvibration the curve shown in Fi 21 is'characteristic are, -by wa of examp e, shown by the circuit S L C Lof Fig. 1 and by the circuit C 1', R. of Fig. 18.

' The curve shown in Fig. 22 represents the variation with time of the currentamplitude in the transmitting-circuit shown in Fig.1 and is generally characteristic of the modes of vibration of the transmitting circuits herein shown. The oscillations are not isochronous throughout their extent, those developed between t and t,,' when the sparkgap is condi'ictive, consisting of a superposition'Tof'two different frequencies, neither ofwhich is equal to that produced when the sparks cease to pass the gap S and when the oscillatingsys tem passes into the closed oscillatin circuit CL C 0 LC (Fig.1.)

'The oscil ations between 15 and t, are'those which are produced'when the spark-gap becomes non-conducting and they are seen to be isochronous throughout their extent and to be of reat persistency. The natural III mode of vi ration characteristic of the conv ductively-connected closed oscillating circuits which contain no responder in Figs. 8, 9, 10, 11,12, 13,14, 17 and 19 would be shown by a curve similar to that part of the curve in Fig. 22 which lies between t, and t,. claim-- 1. In a wireless-telegraph system, an antenna system, an oscillating circuit connectwhich the larger current amplitudes,resulti -"mg in said circuitfrom thecumulatiye-eflect -or selective, receivin -c1rcu1t O R I, The

ed thereto and so constructed and arranged that the two paths from the top of the an-.

tenna to earth are equal in natural eriod, an element having relativel high sipative resistance associated wit said circuit and means for eliminating the effect of said element on the persistency of said circuit.

2. In a wireless-telegraph system, an antenna system, an oscillating circuit connected thereto and so constructed and arranged that the two paths from the top of the antenna to earth are equal in natural eriod, an element having relatively high issipative resistance associated with said circuit and an auxiliary shunt-path containing a capacity connected around said element.

3. In a wireless-telegraph system, an antenna system, an oscillating circuit connected thereto and so constructed and arranged that the two paths from the top of the antenna to earth are equal in natural eriod, an element having relatively high issipative resistance associated with said circuit and an auxiliary shunt-path containing a capacity and an inductance connected around said element.

4. In a wireless -telegraph transmitting system, an antenna system, an oscillatin 4 system connected thereto and so constructe and arranged that the two aths from the top of the antenna to cart are equal in natural period, a spark-gap associated with said circuit and means for eliminating the effect of said spark-gap on the persistency of said circuit.

5. In a wireless telegraph transmitting system, an antenna system, an oscillatin system connected thereto and so constructe and arranged that the two paths from the top of the antenna to earth are equal in natural period, a spark-gap associated with said circuit and an auxiliary shunt-path containing a capacity connected across said spark- 6. In a wirelesstelegraph transmltting system, an antenna system, an oscillatin system connected thereto and so constructe and arranged that the two paths fromthe top of the antenna ,to earth are equal in natural period, a spark-gap associated with said from the top of the antenna to cart circuit and an auxiliary shunt-path containing a capacity and an inductance connected across said spark-gap.

7. In a wireless-telegraph receiving system, an antenna system and a closed oscillating circuit connected thereto and so con structed and arranged that the two aths are equal in natural period.

8. In a wireless-telegraph receiving s. stem an antenna system, ac osed, persistent y oscillating circuit connected thereto and a circuit containing an oscillations-responder connected across the sides of said oscillating circuit.

9. In a wireless-telegraph receivin sy tem, an antenna system, a closed osci atm circuit connected thereto and so constructe and arranged that the two paths from the top of said antenna to earth are equal in natural (period, an oscillation responder associate with said circuit and means for eliminating the effect of said responder on the per sistenc of said circuit.

' 10. n a wireless-telegraph receivin system, an antenna system, a closed oscil atm circuit connected thereto and so constructe and arranged that the two paths from the top of said antenna to earth are equal in natural period, an oscillation-responder associated with said circuit and an auxiliary shunt-path containing a capacity connected across said responder.

11. In a wireless-telegraph receivin system, an antenna system, a closed oscil atm circuit connected thereto and so constructed and arranged that the two paths from the top of said antenna to earth are e ual in natural period, an oscillation respon er associated with said circuit and an auxiliary shunt-path containin a capacity and an inductance connecte across said res onder.

In testimony whereof have hereunto subscribed my name this 9th day of February,

LEE DE FOREST.

Witnesses: Y

M. M. MACRAE, R. O. P WELL. 

